This invention relates to an improved valve seat forming tool and more particularly to a valve seat forming tool which may be used to accurately reform damaged or worn valve seats of an internal combustion engine.
Heretofore various mechanisms have been proposed to reform the valve seat of an internal combustion engine when that engine is being rebuilt. Reforming of the valve seat permits installation of new valve members or reground valves and constitutes an inexpensive way of reconditioning an engine thereby eliminating the necessity to secure a new engine or new engine block.
Among the various prior art references known to applicant which relate to tools for grinding or forming valve seats are the following:
______________________________________ Pat. No. Inventor Title Issue Date ______________________________________ 1,325,278 Dexter Facing Tool For 12/16/19 Dressing Valve Seats 1,487,533 Bryan Valve Seating Tool 3/18/24 1,790,378 Howser Valve Tool 1/27/31 1,837,390 Albertson Valve Seat Recon- 12/22/31 struction Tool 1,843,181 Stougaard Valve Reseating Tool 2/02/32 1,846,890 Miller Valve Reseating Tool 2/23/32 1,899,169 Tyler Tool Holder 2/28/33 1,902,207 Albertson Valve Seat Tool 3/21/33 1,904,941 Dunn Valve Reseating 4/18/33 Tool Driver 1,954,241 Hellyer Milling Tool 4/10/34 1,962,273 Harris et al Seat Facer 6/12/34 1,988,411 Beard Valve Seat 1/13/35 Refacing Tool 2,041,587 Beard Refacing Tool 5/19/36 For Valve Seats 2,082,461 Pardieck Valve Seat Dresser 6/01/37 2,102,707 Holhut Valve Seat Sur- 12/21/37 facing Tool 2,126,789 Lindsey Apparatus for Con- 8/16/38 ditioning Valves and Valve Seats 2,209,021 Hawker Bibb Seating Tool 7/23/40 2,217,772 Rottler Pilot Stem 10/15/40 3,354,528 Appleby Valve Seat Cutter 11/28/67 3,443,480 Wells Means for Securing 5/13/69 Cutters to Tools 3,516,329 Rendahl Cutting Tool for 6/23/70 Valve Seats 3,552,758 Minelli Turning Head for Cutting 8/04/70 et al Valve Seats of Internal- Combustion Engines 3,664,756 Wells Tool Depth Control 5/23/72 Adjustment ______________________________________
The references disclose various mechanisms for reforming, refinishing or grinding a valve seat. Included among the mechanisms are very expensive grinding machines which are attached to the engine block and fit over the seat which is to be resurfaced. Many of the prior art devices position the cutter blades over the valve seat by means of a cantilever support. Using a support of this nature renders alignment of the blades with respect to the valve seat difficult.
Other valve seat tools propose a pilot rod which cooperates with the valve stem opening in the engine block. A cutter assembly is then positioned on the pilot rod.
However, none of the prior art references teach an inexpensive tool which combines the necessary elements to align the cutter blades with respect to the valve seat in a precise and reproducible manner and to permit adjustment of the blades for proper sizing of the valve seat opening and proper inclination of surfaces forming the valve seat. It is believed that the present invention provides the necessary combination of elements in a new and unique manner.